c - typedef __u32 __bitwise __be32 在linux中的意思

Question

我从文件（http://cpansearch.perl.org/src/HAWK/IPTables-libiptc-0.52/include/linux/types.h）中提取这些定义：

#ifdef __CHECKER__
#define __bitwise__ __attribute__((bitwise))
#else
#define __bitwise__
#endif
#ifdef __CHECK_ENDIAN__
#define __bitwise __bitwise__
#else
#define __bitwise
#endif

typedef __u16 __bitwise __le16;
typedef __u16 __bitwise __be16;
typedef __u32 __bitwise __le32;
typedef __u32 __bitwise __be32;
#if defined(__GNUC__)
typedef __u64 __bitwise __le64;
typedef __u64 __bitwise __be64;
#endif
typedef __u16 __bitwise __sum16;
typedef __u32 __bitwise __wsum;

#define bitwise _属性_((bitwise)) 是什么意思？

typedef __u32 __bitwise __be32; 意思是？

Answer 1

In order to understand those macros, I recommend you to read this article: Sparse. Anyway, this question seems to be a duplicate from this: GCC Bitwise Attribute